MILAN, Sept 23 (Reuters) - Italy’s oldest soccer team Genoa became the sixth Serie A side to come under American ownership on Thursday when Miami-based 777 Partners purchased the club from long-time owner Enrico Preziosi.

The private investment firm is the latest U.S. owner in Italy’s top league following AC Milan, Fiorentina, Spezia, AS Roma and Venezia.

Eight of the 20 top-flight Italian clubs now have foreign owners, including China’s Suning Group at Inter Milan and Canadian Joey Saputo at Bologna.

777 Partners will purchase 99.9% of the club's capital, inject fresh funds and "will assume certain related liabilities,," said a joint statement, without giving any financial details of the deal.

“We are deeply honored to become part of a club with a history, heritage and tradition as great as Genoa," added Josh Wander, founder and Managing Partner of 777 Partners.

"We understand and respect the responsibility we are inheriting; we want to preserve and protect the proud legacy of the Rossoblu by aiming for the best possible placing in Serie A."

A Genoa statement said Preziosi will remain on the club’s board of directors, while CEO Alessandro Zarbano will continue to manage day-to-day operations.

Preziosi, head of Italian toy manufacturer Giochi Preziosi, took over in 2003 when the nine-time Italian champions were in Serie B.

The club, founded in 1893, were promoted four years later and has stayed in Serie A ever since.

“I always said that I would only leave Genoa to a strong and reliable new owner and I leave it in the hands of 777 Partners,” Preziosi said.

In addition to Genoa, 777 Partners own a stake in Spanish soccer club Sevilla, as well as UK basketball team London Lions. (Reporting by Elvira Pollina, writing by Cristina Carlevaro, editing by Giulia Segreti and Ken Ferris)